Resize Album Artwork Form mp3 File - ios

Question

I have to resize an album artwork form the file I get with this code:
for (NSString *format in [asset availableMetadataFormats]) {
for (AVMetadataItem *item in [asset metadataForFormat:format]) {
if ([[item commonKey] isEqualToString:#"title"]) {
//NSLog(#"name: %#", (NSString *)[item value]);
downloadedCell.nameLabel.text = (NSString *)[item value];
}
if ([[item commonKey] isEqualToString:#"artist"]) {
downloadedCell.artistLabel.text = (NSString *)[item value];
}
if ([[item commonKey] isEqualToString:#"albumName"]) {
//musicItem.strAlbumName = (NSString *)[item value];
}
if ([[item commonKey] isEqualToString:#"artwork"]) {
UIImage *img = nil;
if ([item.keySpace isEqualToString:AVMetadataKeySpaceiTunes]) {
img = [UIImage imageWithData:[item.value copyWithZone:nil]];
}
else { // if ([item.keySpace isEqualToString:AVMetadataKeySpaceID3]) {
NSData *data = [(NSDictionary *)[item value] objectForKey:#"data"];
img = [UIImage imageWithData:data];
}
// musicItem.imgArtwork = img;
UIImage *newImage = [self resizeImage:img width:70.0f height:70.0f];
downloadedCell.artworkImage.image = newImage;
}
When I apply this method:
- (UIImage *)resizeImage:(UIImage *)image width:(int)width height:(int)height {
//NSLog(#"resizing");
CGImageRef imageRef = [image CGImage];
CGImageAlphaInfo alphaInfo = CGImageGetAlphaInfo(imageRef);
//if (alphaInfo == kCGImageAlphaNone)
alphaInfo = kCGImageAlphaNoneSkipLast;
CGContextRef bitmap = CGBitmapContextCreate(NULL, width, height, CGImageGetBitsPerComponent(imageRef),
4 * width, CGImageGetColorSpace(imageRef), alphaInfo);
CGContextDrawImage(bitmap, CGRectMake(0, 0, width, height), imageRef);
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
UIImage *result = [UIImage imageWithCGImage:ref];
CGContextRelease(bitmap);
CGImageRelease(ref);
return result;
}
I ALWAYS get a noise image like you can see in the photo above.
http://postimage.org/image/jltpfza11/
How can I get a better resolution image?

Answer 1

If your view is 74x74, you should resize to twice that on retina displays. So, something like:
CGFloat imageSize = 74.0f * [[UIScreen mainScreen] scale];
UIImage *newImage = [self resizeImage:img width:imageSize height:imageSize];
Then you need to set the contentMode of your image view to something like UIViewContentModeScaleAspectFill.

Answer 2

Try specify explicitly the level of interpolation for the context using:
CGContextSetInterpolationQuality(bitmap, kCGInterpolationHigh);
Your resizeImage:width:height: method thus becomes:
-(UIImage *)resizeImage:(UIImage *)image width:(int)width height:(int)height {
//NSLog(#"resizing");
CGImageRef imageRef = [image CGImage];
CGImageAlphaInfo alphaInfo = CGImageGetAlphaInfo(imageRef);
//if (alphaInfo == kCGImageAlphaNone)
alphaInfo = kCGImageAlphaNoneSkipLast;
CGContextRef bitmap = CGBitmapContextCreate(NULL, width, height, CGImageGetBitsPerComponent(imageRef),
4 * width, CGImageGetColorSpace(imageRef), alphaInfo);
CGContextSetInterpolationQuality(bitmap, kCGInterpolationHigh);
CGContextDrawImage(bitmap, CGRectMake(0, 0, width, height), imageRef);
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
UIImage *result = [UIImage imageWithCGImage:ref];
CGContextRelease(bitmap);
CGImageRelease(ref);
return result;
}